*{
    padding: 0px;
    margin: 0px;
}
body{
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;

}
.big{
    height: 200px;
    width: 300px;
    background-color: gray;
    display: flex;
    align-items: center;
}
.small{
    height: 50px;
    width: 100px;
    background-color: yellow;
    display: flex;
}